Planarization of metal layers on a semiconductor wafer through non-contact de-plating and control with endpoint detection

ABSTRACT

A non-contact apparatus and method for removing a metal layer from a substrate are provided. The apparatus includes a rotatable anode substrate support member configured to support a substrate in a face-up position and to electrically contact the substrate positioned thereon. A pivotally mounted cathode fluid dispensing nozzle assembly positioned above the anode substrate support member is also provided. A power supply in electrical communication with the anode substrate support member and the cathode fluid dispensing nozzle is provided, and a system controller configured to regulate at least one of a rate of rotation of the anode substrate support member, a radial position of the cathode fluid dispensing nozzle, and an output power of the power supply is provided. The method provides for the removal of a metal layer from a substrate by rotating the substrate in a face up position on a rotatable substrate support member. A cathode fluid dispensing nozzle is positioned over a central portion of the substrate and a metal removing solution is dispensed from the cathode fluid dispensing nozzle onto the central portion of the substrate. An electrical bias is applied between the substrate and the cathode fluid dispensing nozzle, which operates to deplate the metal layer below the fluid dispensing nozzle.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] Embodiments of the present invention generally relate tonon-contact apparatus and methods for deplating a metal layer from asubstrate using an endpoint detection system.

[0003] 2. Description of the Related Art

[0004] Reliably producing sub-quarter micron and smaller features is oneof the key technologies for the next generation of very large scaleintegration (VLSI) and ultra large-scale integration (ULSI) ofsemiconductor devices. However, as the fringes of circuit technology areadvanced, the shrinking dimensions of interconnects in VLSI and ULSItechnologies places additional demands on processing capabilities. Moreparticularly, the multilevel interconnects that lie at the heart of VLSIand ULSI require precise processing of high aspect ratio features, suchas vias, contacts, lines, and other interconnects. Reliable formation ofthese interconnects is important to VLSI and ULSI success and to thecontinued effort to increase circuit density and quality of individualsubstrates and die.

[0005] In order to further improve the current density of semiconductordevices on integrated circuits, it has become necessary to useconductive materials having low resistivity and materials having lowdielectric constants (low k, defined herein as having dielectricconstants, k, less than about 4.0) as insulating layers to reduce thecapacitive coupling between adjacent interconnects. Increased capacitivecoupling between layers can detrimentally affect the functioning ofsemiconductor devices.

[0006] Although aluminum has been the metal of choice in conventionaldevices, copper and its alloys have become the materials of choice forsub-quarter-micron interconnect technology, as copper has a lowerresistivity than aluminum, (1.7 μΩ-cm compared to 3.1 μΩ-cm foraluminum), a higher carrying capacity, and a greater resistance toelectromigration. These characteristics are important for supporting thehigher current densities experienced at high levels of integration andincreased device speed. Additionally, copper exhibits favorable thermalconductivity and is generally available in a relatively pure state.

[0007] One difficulty in using copper in semiconductor devices is thatcopper is difficult to accurately etch and achieve a precise pattern.Etching copper using traditional deposition/etch processes for forminginterconnects has been less than satisfactory, as reliable andconsistent endpoint detection is generally not available withconventional apparatuses and processes. Therefore, the current trend inthe industry is to develop alternative methods and apparatuses forreliably and accurately forming and removing copper layers fromsubstrates, while leaving the copper filled features intact in thesubstrate.

[0008] One method for forming vertical and horizontal interconnects isby a damascene or dual damascene method. In the damascene method, one ormore dielectric materials, such as the low k dielectric materials, aredeposited and pattern etched to form the vertical and horizontalinterconnects. Conductive materials, such as copper-containing materialsand other materials, such as barrier layer materials used to preventdiffusion of copper-containing materials into the surrounding low kdielectric, are then inlaid into the etched pattern. These conductivematerials are deposited in excess in order to insure that the featuresformed in the dielectric layer are adequately filled. However, theexcess copper-containing materials and excess barrier layer materialexternal to the etched pattern, such as on the field of the substrate,must be removed.

[0009] As the various layers of materials are sequentially deposited andremoved in a fabrication process, the uppermost surface of the substratemay become nonplanar across its surface and require planarization.Planarizing a surface, or “polishing” a surface, is a process wherematerial is removed from the surface of the substrate to form agenerally even, planar surface. Planarization is useful in dualdamascene processes to remove excess deposited material and to providean even surface for subsequent levels of metallization and processing.Planarization may also be used in removing undesired surface topographyand surface defects, such as rough surfaces, agglomerated materials,crystal lattice damage, scratches, and contaminated layers or materials.

[0010] Chemical mechanical planarization, or chemical mechanicalpolishing (CMP), is a common technique used to planarize substrates. Inconventional CMP techniques, a substrate carrier or polishing head ismounted on a carrier assembly and positioned in contact with a polishingmedia in a CMP apparatus. The carrier assembly provides a controllablepressure to the substrate urging the substrate against the polishingmedia. The media is moved relative to the substrate by an externaldriving force. Thus, the CMP apparatus effects polishing or rubbingmovement between the surface of the substrate and the polishing mediawhile dispersing a polishing composition to effect both mechanicalactivity and chemical activity.

[0011] Conventionally, in polishing copper features, such as dualdamascene features, the copper-containing material is polished to thelevel of the barrier layer, and then the barrier layer is polished to alevel of the underlying dielectric layer using abrasive polishingsolutions. However, such polishing processes often result in unevenremoval of materials, such as copper in features and the underlyingdielectric layer between features, resulting is the formation oftopographical defects, such as concavities or depressions in thefeatures, referred to as dishing, and excess removal of dielectricmaterial surrounding features, referred to as erosion.

[0012]FIG. 1 is a schematic view of a substrate illustrating dishing andincomplete copper removal. The exemplary substrate 100 includesconductive lines 111 and 12 are formed by depositing conductivematerials, such as copper or copper alloy, in a feature definitionformed in the dielectric layer 110, typically comprised of siliconoxides or other dielectric materials. After planarization, a portion ofthe conductive material in conductive line 112 is depressed by an amount113, referred to as the amount of dishing, forming a concave coppersurface. Additionally, dielectric material, such as around feature 111,may be eroded from the polishing process and expose the sides of thefeatures to subsequent processing steps. Dishing and erosion result in anon-planar surface that impairs the ability to print high-resolutionlines during subsequent photolithographic steps and detrimentallyaffects subsequent surface topography of the substrate and deviceformation. Dishing and erosion also detrimentally affect the performanceof devices by lowering the conductance and increasing the resistance ofthe devices, contrary to the benefit of using higher conductivematerials, such as copper. Further still, the topography of the surfaceand/or the nature of the polishing techniques may also generate areaswhere the copper layer is not completely removed from the dielectricsurface, as generally noted by 114. These remaining copper islands 114,which generally result from poor endpoint detection, are undesirable, asthey facilitate electrical shorting between features of the substrate.

[0013] An additional difficulty also arises when using low k dielectricmaterial in copper dual damascene formation. Low k dielectric materialsare typically soft and porous, and therefore, conventional polishingpressures, which are generally about 4 psi or greater, can damage thelow k dielectric materials and form defects in the substrate surface.Therefore, in order to avoid damaging low k materials duringpolishing/planarizing, the pressure must be reduced. However, polishingsubstrates at reduced pressures often results in less than desirablepolishing rates, non-uniform polishing, and less than desirableplanarization of the substrate surface. Such process difficulties resultin reduced substrate throughput and less than desirable polish qualityof the substrate surface, which may detrimentally affect subsequentprocessing. Additionally, low polishing pressure processes may be unableto sufficiently remove all of the desired copper materials from asubstrate surface such as at the interface between copper and thebarrier layer, which is generally nonplanar. Such copper materialsretained on the substrate surface, or residues, can detrimentally affectdevice formation, such as creating short-circuits within or betweendevices, reduce device yields, reduce substrate throughput, anddetrimentally affect the polish quality of the substrate surface.

[0014] Therefore, there exists a need for a non-contact apparatus andmethod for removing a metal layer from a substrate. Further, there is aneed for an apparatus and method for determining a metal layer removalendpoint.

SUMMARY OF THE INVENTION

[0015] Embodiments of the invention generally provide a non-contactapparatus and method for removing a metal layer from a substrate. Theapparatus includes a rotatable anode substrate support member configuredto support a substrate in a face-up position and to electrically contactthe substrate positioned thereon. A cathode fluid dispensing nozzleassembly is pivotally mounted above the anode substrate support member.A power supply is in electrical communication with the anode substratesupport member and the cathode fluid dispensing nozzle. A systemcontroller is configured to regulate at least one of a rate of rotationof the anode substrate support member, a radial position of the cathodefluid dispensing nozzle, and an output power of the power supply.

[0016] Embodiments of the invention further provide an apparatus forelectrochemically removing a metal layer from a substrate surface,wherein the apparatus includes a processing chamber having a rotatableanode substrate support member positioned therein and a radially mountedcathode fluid dispensing assembly positioned in the processing chamber,the cathode fluid dispensing assembly being in communication with apivotal actuator configured to selectively adjust a radial position ofthe cathode fluid dispensing assembly. A power supply having an anodeterminal in electrical communication with the anode substrate supportmember and a cathode terminal in communication with the cathode fluiddispensing assembly is provided, and a microprocessor controller incommunication with the pivotal actuator, the microprocessor controllerbeing configured to control the radial position of the cathode fluiddispensing assembly relative to a center of the substrate via selectiveactuation of the pivotal actuator is also provided.

[0017] Embodiments of the invention further provide a method forremoving a metal layer from a substrate, wherein the method includesrotating a substrate in a face up position on a rotatable substratesupport member, positioning a cathode fluid dispensing nozzle mounted ona distal end of a pivotally mounted fluid dispensing arm over a centralportion of the substrate, and dispensing a metal removing solution fromthe cathode fluid dispensing nozzle onto the central portion of thesubstrate. The method further includes applying an electrical biasbetween the substrate and the cathode fluid dispensing nozzle, andadjusting a radial position of the cathode fluid dispensing nozzleoutward from the central portion of the substrate when a parameter ofthe electrical bias exceeds a predetermined threshold.

[0018] Embodiments of the invention further provide a method forcontrolling an electrochemical deplating process. The method includesmonitoring at least one of a plating circuit voltage and a platingcircuit resistance, and adjusting a radial position of a nozzledispensing an electrolytic solution onto a substrate in order to deplatea metal layer therefrom when at least one of the plating circuit voltageand the plating circuit resistance exceeds a predetermined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] So that the manner in which the above recited features,advantages and objects of the present invention are attained and can beunderstood in detail, a more particular description of the invention,briefly summarized above, may be had by reference to the embodimentsthereof which are illustrated in the appended drawings.

[0020] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0021]FIG. 1 illustrates a low k material based substrate planarizedwith a conventional CMP process.

[0022]FIG. 2 illustrates an exemplary deplating chamber of theinvention.

[0023]FIG. 3 illustrates a perspective view of an exemplary substratesupport member and a partial sectional view of contact ring of theinvention.

[0024]FIG. 4 illustrates a sectional view of an exemplary substratesupport member of the invention.

[0025]FIGS. 5a-5 e illustrate an exemplary deplating sequence of theinvention.

[0026]FIG. 6 illustrates a plan view of an exemplary embodiment of theinvention.

[0027]FIG. 7 illustrates an exemplary plan view of a substrate during aplating process of the invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028]FIG. 2 generally illustrates a sectional view of an exemplaryelectro chemical deplating process cell 200 of the invention. Deplatingcell 200 includes a processing compartment 202 having a top 204,sidewalls 206, and a bottom 207. A substrate support member 212, whichis shown in perspective in FIG. 3 and in section in FIG. 4, is disposedin a generally central location within chamber 200. Substrate support212 includes a substrate receiving surface 214 on the upper side thereofthat is configured to receive a substrate in a “face-up” position, i.e.in a position where the production surface of the wafer is facing awayfrom the substrate support member 212. Substrate support member 212 maybe, for example, manufactured from an insulative material, such asceramic materials, alumina (Al₂O₃), a Teflon® coated metal (such asaluminum or stainless steal), silicon carbide (SiC), or other materialssuitable for deplating processes. An insulative anode electrical contactring 300 is mounted to the receiving surface 214 of substrate support212 proximate the perimeter of substrate support 212, and includes aplurality of conductive electrical contacts 302 extending therefrom andan annular seal member 304 in communication therewith. Receiving surface214 may include one or more vacuum channels, ports, or apertures 305that are in communication with a vacuum source (not shown) via a conduit310 formed into substrate support member 212. Therefore, channels 305,when supplied with a negative pressure from the vacuum source, areconfigured to secure or chuck a substrate to substrate support member212 for processing. The substrate is generally chucked to the substratesupport member 212 with the backside or non-production surface of thesubstrate facing the substrate support member 212. Therefore, theproduction surface of the substrate will be exposed or facing away fromreceiving surface 214. This configuration allows ring 300 toelectrically contact the non-production or backside of the substrate viaelectrical contacts 302. Alternatively, contact ring 300 and contacts302 may be configured to electrically engage the production surface ofthe substrate proximate the perimeter thereof in the exclusion zone, forexample. A motor 222 may be coupled to the substrate support 212 inorder to selectively rotate the substrate support 212 to spin asubstrate positioned thereon.

[0029] Anode contact ring 300 is generally fixedly attached to thereceiving surface 214 of substrate support 212 proximate the outerperimeter of support 212. Alternatively, anode contact ring 300 may beintegrally formed into the receiving surface 214 of substrate support212, thus creating a unitary substrate support member and anode contactring. Seal member 304 may be an O-ring type seal, and the plurality ofelectrical contacts 302 may be positioned radially inward from seal 304.Seal 304 operates to provide a seal/barrier that prevents fluidsolutions, i.e., an electrolytic deplating solution, fromflowing/traveling to the back side/contact side of substrate 211, andtherefore, provides a dry contact configuration. However, the presentinvention is not limited to configurations using an outer sealconfiguration, as it is contemplated that the seal may be positionedradially inward from contacts 302 in a wet contact-type configuration.Seal 304 may be manufactured from various materials known in the art toprovide sealing capability and to maintain physical integrity in thepresence of a deplating solutions. Examples of materials that may beused for seal 304 include plastic compounds, Teflon® compounds, Nylon®compounds, rubber compounds, and other materials used to manufactureseals known to be acceptable sealing materials for deplatingapparatuses. Further, the outer surfaces of contact ring 300 that areexposed to the deplating solution are preferably coated or treated toprovide a hydrophilic surface in order to encourage solution flow andcontact therewith. Contact ring 300 may be manufactured from aninsulative material, such as an insulative plastic,polyvinylidenefluoride (PVDF), perfluoroalkoxy resin (PFA), Teflon®,Tefzel™, Alumina (Al₂O₃), ceramics, and/or other suitable insulativematerials.

[0030] The plurality of wafer contacts 302, which are manufactured froman electrically conductive material, are generally in communication withone or more electrical supply contacts 303 positioned on receivingsurface 214 adjacent the plurality of electrical contacts 302, as shownin FIG. 4. Electrical supply contacts 303 may be used to communicateelectrical energy from a power supply 210, which is in electricalcommunication with the electrical supply contacts 303 via conductors309, to the plurality of electrical contacts 302. Power supply 210 maybe a DC power supply configured to generate a constant DC output, oralternatively, power supply 210 may be configured to generate various DCwaveforms, such as square waveforms, sinusoidal waveforms, saw-toothwaveforms, and/or other waveforms that may be generated by a powersupply. The electrical supply contacts 303 may be a unitary conductiveannular ring formed into the receiving surface 214 of substrate support212, wherein the ring is configured to electrically engage each of theplurality of electrical contacts 302 in the anode contact ring 300 whenring 300 is mounted to substrate support 212. Alternatively, electricalsupply contacts 303 may comprise a plurality of individual electricalsupply contacts 303 formed into the receiving surface 214 of substratesupport 212. In this configuration, each of contacts 303 may be radiallypositioned to cooperatively contact and electrically engage anindividual one of the plurality of electrical contacts 302 in the anodecontact ring 300. Therefore, each of contacts 303 may be configured tosupply a specific individual electrical bias to each of contacts 302,through, for example, the use of a controller 230 configured toindividually regulate the electrical bias applied to each of contacts302 in order to control the uniformity of the electrical bias applied tothe substrate 211. The regulation of the electrical bias applied to eachof the contacts 302 may be, for example, implemented through aselectively controllable variable resistor positioned in series witheach of contacts 302. Other alternative methods, apparatuses, andcircuits may be used to control the electrical current and/or voltageapplied to the contacts 302. Regardless of the configuration, supplycontact(s) 303 operate to communicate electrical energy to the pluralityof electrical contacts 302 in anode contact ring 300. Contacts 302,which are configured to electrically engage a backside conductivesurface of substrate 211, may be manufactured from an electricallyconductive material, such as copper (Cu), platinum (Pt), tantalum (Ta),titanium (Ti), gold (Au), silver (Ag), stainless steel, or otherconductive materials compatible with semiconductor manufacturingprocesses. Low resistivity and low contact resistance, which are desiredcharacteristics for contacts 302, may further be achieved by coatingcontacts 302 with an additional conductive material. Therefore, contacts302 may, for example, be made of copper (resistivity for copper isapproximately 2×10⁻⁸ Ω·m) and be coated with platinum (resistivity forplatinum is approximately 10.6×10 ⁻⁸ Ω·m). Coatings such as tantalumnitride (TaN), titanium nitride (TiN), rhodium (Rh), Au, Cu, or Ag maybe used on conductive base materials, such as stainless steel,molybdenum (Mo), Cu, and Ti. Contacts 302 may further be configured flexor bend upon contacting a substrate. This allows each of contacts 302 tocooperatively engage the substrate, as contacts that first engage thesubstrate upon placement of the substrate on ring 300 simply bend orflex to allow the remaining contacts 302 to simultaneously engage thesubstrate.

[0031] A cathode fluid dispensing unit, such as a rotatably mountednozzle 223, may be disposed in chamber 200. Nozzle 223 may be configuredto deliver a fluid, such as an electrolytic deplating solution, anetchant, deionized water, and/or an acid solution, to the surface ofsubstrate 211 positioned on support 212. Nozzle 223 is attached to andis in fluid communication with a longitudinally extending arm 224, whichhas a substantially hollow interior portion that may be used tocommunicate fluids therethrough to nozzle 223. Arm 224 may be pivotallyattached to support member 225, which also includes a fluid conduit 226therein that may be used to communicate fluids therethrough to arm 224.Support member 225 may be rigidly attached to chamber bottom 207, oralternatively, support member 225 may be rotatably attached to chamberbottom 207 if arm 224 is rigidly attached to support member 225. As aresult of the pivotal motion available from either arm 224 or supportmember 225, nozzle 223 may be positioned over the center of substrate211 in order to deliver a fluid to the center of the substrate 211, andthen nozzle 223 may be rotated about axis 201 in order to selectivelydispense fluid across the surface of substrate 211 when substrate 211 isrotated. For example, as nozzle 223 is pivoted outward from the centerof substrate 211, the fluid dispensed therefrom flows outward over anannular band of substrate 211 having a circular inner boundary thatcorresponds to the radial position of nozzle 223 from the center ofsubstrate 211.

[0032] Nozzle 223 is generally in communication with a cathode source,such as the negative output of power supply 210, for example, whichallows for an electrical potential to be applied between substrate 211and nozzle 223, as a result of the positive terminal of power supply 210being in electrical communication with substrate 211. As such, thedeplating solution dispensed from nozzle 223 will generally be aconductive fluid, which allows the electrical potential applied tonozzle 223 to be communicated to substrate 211 via the conductivedeplating solution. The electrical potential or bias applied between thesubstrate surface, which is configured as an anode in the presentexemplary embodiment, and the cathode nozzle 223, operates to bothaccelerate the deplating process and to provide a monitorable endpointcontrol function, which will be further discussed herein. The size andshape of nozzle 223 may be adjusted in order to vary the rate of metaldeplating. Chamber 200 further includes a drain 227 configured tocollect fluids used in the chamber, and more particularly, fluidsdispensed from nozzle 223 that run off the edge of substrate 211 andfall to the chamber bottom 207. In an alternative embodiment, nozzle 223may be attached to a side wall 206 of chamber 200 through an arm 224that extends to side wall 206. In this embodiment arm 206 may bepivotally mounted to side wall 206 in order to allow nozzle 223 to bepositioned over various radial positions of the substrate.Alternatively, arm 224 may be configured to be selectivelylongitudinally extended, thus allowing nozzle 223 to be positioned overvarious radial positions over the substrate 211.

[0033] An actuator 231, positioned proximate support member 225, may beused to selectively pivot or rotate support member 225 and/or arm 224about axis 201. Therefore, actuator 231 may be used to vary or adjustthe radial position of nozzle 223 relative to axis 201, which alsooperates to vary the position of nozzle 223 relative to the center ofsubstrate 211 being processed. Actuator 231, for example, may be astepping motor configured precisely pivot arm 224 about axis 201 inorder to vary the position of nozzle 223 relative to the center ofsubstrate 211. The actuation of stepping motor 231 may be managed by anelectronic controller 230 in communication therewith. Controller 231 maybe a microprocessor based control system configured to receive controlinput from a user and various devices/sensors in system 200, execute acontrol program, and output control signals to various components ofsystem 200. Therefore, in addition to controller 230 being incommunication with actuator 231, controller 230 may also be incommunication with motor 222 and power supply 210 in order to providecontrolling signals thereto. As such, controller 230 may operate toregulate the rotation rate of substrate support 212 and the output ofpower supply 210. Actuator 231 may alternatively be used tolongitudinally extend arm 224 to position nozzle 223 over selectedradial positions of the substrate 211.

[0034] In operation, an apparatus of the invention may be used to removea metal layer from a substrate. For example, during semiconductorprocessing, a copper layer may be deposited on a substrate to fillfeatures 502 formed in the substrate 500, as illustrated in FIG. 5a. Thecopper fill layer 501 will generally be over deposited in order tocompletely fill the features 502, and therefore, the over depositedcopper, which generally forms a continuous layer over the substratesurface, must be removed to reveal the individual copper filled features502. In this situation, the substrate 500 having the over depositedcopper layer 501 thereon may be placed in chamber 200 of the inventionfor removal of the over deposited copper layer 501. Substrate 500 may betransferred into chamber 200 via a transfer robot (not shown) configuredto place substrate 500 on substrate receiving surface 214 of substratesupport 212. The transfer robot may access chamber 200 via an opening208 in a sidewall 206 of chamber 200, where opening 208 is incommunication with the processing compartment 202. Once substrate 500 isplaced on substrate receiving surface 214, the substrate 500 may besecured or chucked to substrate support member 212. Although variousmechanical chucking and securing methods are contemplated within thescope of the invention, preferably, substrate 500 is vacuum chucked tosubstrate support member 212 using backside substrate contacts, whichallows for uninterrupted fluid flow across the surface of substrate 500.

[0035] However, in a deplating process using a back side contactconfiguration of the invention, a substrate 500 having a metal layer 501to be removed from above metal filled features 502 must first have abackside conductive layer 503 deposited thereon. If a conventional frontside contact configuration is implemented, through, for example, the useof a front side contact ring positioned above substrate support 212 andbeing configured to be lowered onto the front side of substrate 211 andmake electrical contact therewith, then the deposition of the backsideconductive layer is unnecessary. In backside contact configurations, thebackside conductive layer generally operates to conduct an electricalbias applied to substrate 500 by backside electrical contacts 302 to themetal layer 501 to be removed from the production surface or front sideof substrate 500. Therefore, a backside conductive layer 503 willgenerally be deposited around the edge or bevel 506 to the backside ofsubstrate 500, as illustrated in FIG. 5b. The deposition of backsideconductive layer 503 may be accomplished though known depositiontechniques, such as CVD, an electroless deposition process, or otherdeposition techniques. The deposition of backside conductive layer 503will generally be conducted in a separate chamber, however, the presentinvention contemplates that the deposition of backside conductive layer503 may be accomplished within chamber 200, assuming that theappropriate mechanical features for the particular deposition processwere incorporated into chamber 200. A deposition seal or barrier 504 maybe used in the deposition process of backside conductive layer 503 inorder to limit the deposition width of conductive backside layer 503 toa predetermined area or band proximate the periphery of substrate 500.The predetermined backside deposition area or band may be calculated tobe sufficient to establish backside contact, while not requiringsubstantial additional effort to remove the backside conductive layer503. Therefore, the width of deposition may be, for example, betweenabout 3 millimeters and about 6 millimeters, as this width rangegenerally allows sufficient area for electrical contact and sealconfigurations. Additionally, the other physical characteristics ofbackside layer 503, such as layer thickness, layer uniformity, and layerresistivity, for example, may be selected to provide optimal electricalconductivity to the metal layer 501 through a minimal resistance path,so that the current provided to metal layer 501 during the deplatingprocess may be essentially equal around the circumference of wafer 500.

[0036] Once backside conductive layer 503 is deposited, the deplatingprocess for metal layer 501 of substrate 500 may be initiated. As notedabove, the deplating process begins with substrate 500 being chucked tosubstrate support 212, as illustrated in FIG. 5c. The chucking processcauses backside conductive layer 503 to be in electrical communicationwith the plurality of electrical contacts 302. As a result of chuckingand contacting the substrate on the backside, the production surface ofthe substrate and the exclusion zone surrounding the production surfaceare not mechanically or electrically contacted, as with conventionaldevices. This configuration is generally termed a “non-contact”apparatus, as the production surface of the wafer is not contacted bythe apparatus during the deplating process. Further, the cathode nozzle223 also does not physically contact the substrate, as conventionalcathodes do, thus further supporting the non-contact configuration. Thechucking process also causes seal 304 to engage the back surface ofsubstrate 500. This operates to generate a dry contact configuration,i.e., the contacts are sealed from the solution that is flowed over thesubstrate surface by seal 304. Once the substrate 500 is securelychucked and in electrical communication with contacts 302 motor 222 isenergized by controller 230 and substrate support 212 begins to rotateat a predetermined rate. Nozzle 223 is then positioned immediately abovethe center of substrate 500 via actuation of stepping motor 231 bycontroller 230. Power supply 210 is activated by controller 230 in orderto apply an electrical bias between the metal layer 501 via the anodecontact ring 300 and the cathode fluid delivery nozzle 223. Once nozzle223 is positioned above the center of substrate 500, substrate support212 is rotating, and power supply 210 is activated, nozzle 223 begins toflow an electrically conductive electrolytic metal deplating solutiononto center portion 601 of substrate 500, as illustrated in FIG. 6. Theelectrolytic deplating solution operates to both facilitate thedeplating of metal layer 501, as well as to complete an electricalplating circuit.

[0037] The plating circuit may generally include the electrical pathbetween the respective terminals of the power supply 210. In theembodiment of the invention illustrated in FIG. 2, the plating circuitwould be the electrical circuit formed by the power supply 210, thecathode fluid dispensing nozzle 223, the anode contact ring 300, and theconductive deplating solution flowing between nozzle 223 and thesubstrate 211 positioned on ring 300. Thus, an electrical bias appliedby power supply 210 may be conducted through and nozzle assembly 223 andapplied to the substrate surface by the conductive deplating solution.The metal layer on the substrate surface conducts the electrical bias tothe contact ring 300, which is in electrical communication with thepower supply, thus completing the circuit. Chamber 200 is configured todeplate metal, and therefore, nozzle 223 is configured as the cathode,while the contact ring 300 is configured as the anode. The preciselocation of the cathode source may be varied between applications. Forexample, the deplating solution may be contained in a conductive cathodecontainer that is in fluid communication with base member 225 andelectrical communication with power supply 210. In this configuration,the cathode source/conductive cathode container may be located remotelyfrom chamber 200. Alternatively arm 224 and/or nozzle 223 may bemanufactured from a conductive material and be in electricalcommunication with power supply 210, and therefore, operate as thecathode.

[0038] The rate of rotation of substrate support 212 may be in the rangeof about 5 RPM up to about 10,000 RPM, depending upon the specificcentrifugal force desired for the particular removal application. Duringthe deplating processes, the rotation rate of substrate support member212 may be between about 20 RPM and about 100 RPM. The rotation rate maybe substantially increased to between about 500 RPM and about 2000 RPMduring a drying process. Power supply 210 generally applies a constantDC voltage to the substrate during deplating processes. However, theapplied voltage may be varied through application of a DC waveformgenerated by power supply 210, as mentioned above. The DC waveformapplied to the substrate may be positive, negative, or a combination ofpositive and negative voltages, depending upon the waveform applied. Inthe exemplary embodiments of the invention, for example, a voltagebetween about 20 and about 40 volts may be applied to the substrateusing a current of between about 30 amps and about 50 amps, for example.However, it is understood that types of features and chemistries used todeplate metal have a substantial effect upon the voltage and currentthat is required to deplate metal. The chemical solution, i.e., themetal removing solution dispensed from nozzle 223, may be, for example,a sulfuric acid solution (H₂SO₄), a hydrogen peroxide solution (H₂O₂), acopper sulfate solution (CuSO₄), or other chemical solution known toreact with copper. The deplating solution may include a dilutingelement, which may be a fluoride solution or another glycol-typeadditive, for example. Regardless of the acidic solution used, the ph ofthe solution may be, for example, about 1. The solution generally flowsradially outward across the substrate surface in the direction indicatedby arrows 602.

[0039] When the chemical deplating solution contacts the substratesurface, an electrochemical reaction takes place that operates to removethe copper layer from the substrate surface proximate the point ofcontact with the chemical solution, i.e., at the location below nozzle223. Therefore, during the initial stages of the removal process, i.e.,when nozzle 223 is positioned above the center 601 of substrate 500, themetal layer 501 above center 601 is removed from substrate 500. However,when the metal layer 501 above center 601 is removed, the electricalcircuit through power supply 210, nozzle 223, and metal layer 501 viacontacts 302 experiences a substantial change in resistance. Thissubstantial change in resistance, which is generally a resistanceincrease, is a result of a portion of the current path for the circuitbeing removed, i.e., the metal layer 501 operates as a conductor for thecircuit, as metal layer 501 generally connects nozzle 223 to backsidecontacts 302. Therefore, when the metal layer 501 below nozzle 223(above center 601) is removed, the current path from nozzle 223 tocontacts 302 is broken or diminished, which results in a noticeableincrease in the circuit voltage.

[0040] Since power supply 210 is generally configured to output aconstant current during the deplating/metal layer removal process, theincrease in circuit voltage resulting from metal layer 501 being removedfrom the area below nozzle 223 may be measured and/or monitored bycontroller 230. Therefore, when the circuit voltage increases above apredetermined threshold, where the threshold is calculated to representthe point where metal layer 501 is removed from the area below nozzle223, controller 230 may be configured to adjust the radial position ofarm 224 so that nozzle 223 is over an area of metal layer 501 that hasnot been removed yet. For example, FIG. 7 illustrates substrate 500during the metal removal process. Initially, nozzle 223 will bepositioned above substrate center 601, and therefore, the metal layer501 in region 700 proximate center 601 will be removed. Once metal layer501 in central region 700 is removed, the voltage in the circuit willincrease. Controller 230 monitors the increased voltage and actuatesstepping motor 231 in response thereto, which adjusts the radialposition of arm 224 so that nozzle 223 is over annular region 701 wheremetal layer 501 has not yet been removed. The metal removal processcontinues until the voltage in the circuit again increases past thepredetermined threshold indicating that the metal layer 501 in annularregion 701 has been removed. When the voltage increases past thethreshold, controller 231 again adjusts the radial position of arm 224to position nozzle 223 over annular region 702 where the metal layer 501has not yet removed. This process continues successively throughnumerous annular regions of substrate 500 until nozzle 223 reaches theperimeter 703 of substrate 500. Therefore, generally, as the metal layerremoval process continues, the radial position of arm 122 may beadjusted outward from center 601 by controller 230 in order tofacilitate removal of the remaining metal layer 501 from the outerportion 604 of substrate 500, as illustrated in FIG. 6. The direction ofradial or pivotal movement of arm 224 is shown by arrow 605, andgenerally includes a radial or pivotal movement of arm 224 that causesnozzle 223 to be moved away from the center 601 of substrate 500.

[0041] During the metal removal process, the electrolytic chemicalsolution that flows from nozzle 223 across the substrate surface isurged toward the perimeter of substrate 500 by the centrifugal forcegenerated by the rotation thereof. The flow rate across the surface ofthe substrate 500 may be adjusted by increasing or decreasing the rateof rotation of substrate support 212, where a faster rotation will causethe flow of the electrolytic solution across the substrate surface to beaccelerated. This flow rate is important to proper metal layer removal,as a slow flow rate of the solution across the surface of the substrate500 may allow the solution to permeate the over deposited metal layerand begin to remove the metal deposited in the features 502 of thesubstrate. Therefore, the rate of rotation is generally calculated to besufficient to cause the chemical solution to flow away from the centerof the substrate 500 at a sufficient rate to keep the chemical solutionfrom removing metal from the features of the substrate 500 beneath theover deposited metal layer. As such, the chemical solution generallytravels across the substrate surface toward the perimeter and runs offthe edge and falls onto bottom portion 207 of chamber 200. Bottomportion 207 may be tapered or slanted in order to direct the fluidfalling from substrate support 212 toward a fluid recovery drain 227.

[0042] Additionally, in order to further regulate and monitor theremoval rate of the metal layer across the surface of the substrate, adilution nozzle 606 positioned on arm 224 may be used to flow aneutralizing fluid onto the substrate surface at a position outside ofnozzle 223. The neutralizing fluid dispensed from nozzle 606, which maybe deionized water, for example, may operate to dilute the chemicalsolution dispensed from nozzle 223 to a point where the chemicalsolution no longer removes metal from the substrate surface on thesurface area of the substrate outside of nozzle 223. Further, thedilution nozzle 606 may increase the resistivity of the fluid flowingacross the substrate surface, which operates to contain the bulk of theelectrical flow to metal layer 501. Therefore, the dilution nozzle 606operates to both contain the metal removal process to the area proximatenozzle 223 and to encourage the current flowing from nozzle 223 tocontacts 302 to flow through metal layer 501 and not the fluid passingover the surface of substrate 500.

[0043] Once the metal layer 501 has been removed from the substratesurface, i.e. once the radial position of arm 224 has been pivotedthrough a range that allows nozzle 223 to reach the edge or perimeter ofsubstrate 500, as shown in FIG. 5d, then the metal removal process forthe production surface is complete. At this stage, although metal layer501 is removed, the metal remains within features 502. However, backsideconductive layer 503 must generally be removed from the bevel 506 andbackside of substrate 500. An edge bead removal process, a deplatingprocess, or other metal removal process may be used to remove backsideconductive layer 503 from substrate 500. Once backside conductive layer503 is removed, as shown in FIG. 5e, the metal layer removal process forsubstrate 500 is generally complete.

[0044] While the foregoing is directed to embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A apparatus for removing a metal layer from a substrate, comprising: a rotatable anode substrate support member configured to support a substrate; a cathode fluid dispensing nozzle assembly positioned above the anode substrate support member; a power supply in electrical communication with the anode substrate support member and the cathode fluid dispensing nozzle; and a system controller configured to regulate at least one of a rate of rotation of the anode substrate support member, a position of the cathode fluid dispensing nozzle, and an output power of the power supply.
 2. The apparatus of claim 1, wherein the system controller comprises a microprocessor device in electrical communication with the power supply, a cathode fluid dispensing nozzle actuator, and an anode substrate support member motor, the microprocessor device being configured to receive user and system parameter input, and generate output control signals therefrom.
 3. The apparatus of claim 2, wherein the system controller is configured to receive and control a plating circuit voltage.
 4. The apparatus of claim 1, wherein the rotatable anode substrate support member comprises: a rotatably mounted shaft in communication with a motor, the motor being configured to impart rotational motion to the shaft; and a substrate support surface concentrically mounted to a distal end of the shaft, the substrate support surface being configured to receive a substrate in a face up position.
 5. The apparatus of claim 4, wherein the substrate support surface further comprises an annular anode contact ring positioned about a perimeter of the substrate support surface, the anode contact ring having one or more electrical substrate contacts formed therein.
 6. The apparatus of claim 5, wherein the anode contact ring further comprises an annular seal member positioned radially outward from the plurality of electrical substrate contacts.
 7. The apparatus of claim 5, wherein the one or more electrical contacts are in electrical communication with a positive output of the power supply.
 8. The apparatus of claim 1, wherein the cathode fluid dispensing nozzle is in electrical communication with a negative output of the power supply.
 9. The apparatus of claim 1, wherein the substrate support member further comprises a substrate receiving surface having a plurality of apertures formed therein, each of the plurality of apertures being in communication with a vacuum source and configured to vacuum chuck the substrate to the substrate receiving surface.
 10. The apparatus of claim 1, wherein the cathode fluid dispensing nozzle assembly further comprises: a base member having a fluid conduit formed therein; a longitudinally extending arm member having a substantially hollow interior portion, the arm member being affixed to a distal end of the base member so that the substantially hollow interior portion is in fluid communication with the fluid conduit of the base member; a cathode fluid dispensing nozzle positioned at a distal end of the arm member and being configured to dispense a fluid onto the substrate positioned thereunder, the cathode fluid dispensing nozzle being in electrical communication with a negative terminal of the power supply; and an arm actuator in communication with the arm member for selectively varying a radial position of the arm member.
 11. The apparatus of claim 10, wherein the system controller is configured to vary the radial position of the arm member in response to an increased voltage at the power supply.
 12. The apparatus of claim 10, wherein the system controller is configured to monitor a voltage in a plating circuit and vary a radial position of the arm member when the monitored voltage exceeds a predetermined voltage threshold.
 13. The apparatus of claim 12, wherein the predetermined voltage threshold corresponds to removal of the metal layer is from an area immediately below the cathode fluid dispensing nozzle assembly.
 14. The apparatus of claim 10, wherein the arm member further comprises a second fluid dispensing nozzle positioned intermediate the distal end and the base member, the second fluid dispensing nozzle being configured to dispense a neutralizing fluid onto the substrate at a point radially outward from the cathode fluid dispensing nozzle.
 15. The apparatus of claim 1, further comprising a fluid delivery system having at least one fluid source and at lease one fluid supply control valve in communication with each of the at least one fluid sources, each of the at least one fluid supply control valves being in communication with cathode fluid dispensing nozzle assembly.
 16. The apparatus of claim 1, wherein the substrate support member further comprises a selectively actuated lift pin assembly positioned below the substrate support member, the lift pin assembly being configured to lift the substrate from the substrate support member for removal therefrom by a transfer robot.
 17. The apparatus of claim 1, wherein the apparatus is a non contact apparatus.
 18. The apparatus of claim 1, wherein the rotatable anode substrate support is configured to support a substrate in a face-up position and to electrically contact a backside of the substrate.
 19. The apparatus of claim 1, wherein the cathode fluid dispensing nozzle is pivotally mounted and configured to be radially positioned over the metal layer of the substrate.
 20. The apparatus of claim 1, wherein the controller is configured to regulate a radial position of the cathode fluid dispensing nozzle over the substrate.
 21. An apparatus for electrochemically removing a metal layer from a substrate surface, comprising: a processing chamber having a rotatable anode substrate support member positioned therein; and a radially mounted cathode fluid dispensing assembly positioned in the processing chamber, the cathode fluid dispensing assembly being in communication with a pivotal actuator configured to selectively adjust a radial position of the cathode fluid dispensing assembly; a power supply having a an anode output in electrical communication with the anode substrate support member and a cathode output in electrical communication with the cathode fluid dispensing assembly; and a microprocessor controller in communication with the pivotal actuator, the microprocessor controller being configured to control the radial position of the cathode fluid dispensing assembly relative to a center of the substrate.
 22. The apparatus of claim 21, wherein radially mounted cathode fluid dispensing member comprises: a base member mounted to the processing chamber, the base member having a fluid conduit formed therein for communicating a fluid therethrough; an elongated arm member pivotally mounted to the base member and having a substantially hollow interior portion forming at least one fluid conduit therethrough; and at least one cathode fluid dispensing nozzle mounted to a distal end of the arm member and being in fluid communication with the at least one fluid conduit.
 23. The apparatus of claim 22, wherein the at least one cathode fluid dispensing nozzle further comprises: a first cathode fluid dispensing nozzle mounted on a distal end of the arm member, the first cathode fluid dispensing nozzle being configured to dispense a metal removing electrolytic solution onto the substrate; and a second fluid dispensing nozzle mounted on the arm member between the first fluid dispensing nozzle and the base member, the second fluid dispensing nozzle being configured to dispense a neutralizing solution onto the substrate at a position radially outward from the center of the substrate relative to the first fluid dispensing nozzle.
 24. The apparatus of claim 21, wherein the rotatable anode substrate support member comprises: a rotatable shaft member having a substantially hollow interior portion; a disk shaped substrate receiving surface concentrically mounted to the shaft member; and a stepping motor in communication with the rotatable shaft member, the motor being configured to impart rotational motion to the shaft member in order to rotate the disk shaped substrate receiving member.
 25. The apparatus of claim 24, wherein the rotatable anode substrate support member further comprises an annular anode contact ring positioned proximate a perimeter of the anode substrate support member, the anode contact ring being configured to electrically engage a backside of the substrate.
 26. The apparatus of claim 25, wherein the anode contact ring comprises: an insulative annular body portion; a plurality of conductive electrical contacts radially positioned about the circumference of the annular body portion and extending therefrom; and an annular seal member positioned radially outward from the plurality of conductive contacts, the annular seal member being configured to create a dry contact configuration.
 27. The apparatus of claim 26, wherein the plurality of conductive electrical contacts are cooperatively in electrical communication with an anode output of the power supply.
 28. The apparatus of claim 23, wherein the first cathode fluid dispensing nozzle is in communication with a cathode output of the power supply.
 29. The apparatus of claim 21, wherein power supply forms a deplating circuit with the anode substrate support member, a deplating solution, and the cathode fluid dispensing assembly.
 30. The apparatus of claim 29, wherein the controller is configured to monitor a deplating circuit voltage and pivotally adjust a radial position of the cathode fluid dispensing assembly relative to a center of the substrate when the deplating sircuit voltage exceeds a predetermined threshold voltage.
 31. The apparatus of claim 21, wherein the rotatable anode substrate support member further comprises a lift pin assembly configured to lift a substrate from the substrate receiving surface for removal from the processing chamber by a robot.
 32. The apparatus of claim 21, wherein the controller is configured to monitor a parameter of a plating circuit and adjust a radial position of the cathode fluid dispensing assembly in response to the parameter exceeding a predetermined threshold.
 33. The apparatus of claim 32, wherein the parameter is at least one of a plating circuit voltage and a plating circuit resistance.
 34. A method for removing a metal layer from a substrate, comprising: rotating a substrate in a face up position on a rotatable substrate support member; positioning a cathode fluid dispensing nozzle over a central portion of the substrate; dispensing a metal removing solution from the cathode fluid dispensing nozzle onto the central portion of the substrate; and applying an electrical bias between the substrate and the cathode fluid dispensing nozzle.
 35. The method of claim 34, further comprising adjusting a radial position of the cathode fluid dispensing nozzle outward from the central portion of the substrate in response to a parameter r of the electrical bias exceeds a predetermined threshold.
 36. The method of claim 34, wherein applying the electrical bias further comprises electrically connecting a negative output of a power supply to the cathode fluid dispensing nozzle and electrically connecting a positive output of the power supply to the substrate.
 37. The method of claim 36, wherein connecting the positive output of the power supply to the substrate comprises electrically contacting a backside conductive layer on the substrate with an anode contact ring positioned on the substrate support member.
 38. The method of claim 37, wherein electrically contacting the backside conductive layer further comprises electrically engaging the backside conductive layer with a plurality of radially positioned conductive electrical contacts formed into the anode contact ring.
 39. The method of claim 38, wherein each of the plurality of radially positioned conductive electrical contacts are in electrical communication the positive output of the power supply.
 40. The method of claim 34, wherein adjusting a radial position of the cathode fluid dispensing nozzle comprises: monitoring at least one of a plating circuit voltage and a plating circuit resistance with a system controller; and adjusting the radial position of the cathode fluid dispensing nozzle when at least one of the plating circuit voltage and the plating circuit resistance exceeds the predetermined threshold.
 41. The method of claim 34, wherein adjusting the radial position of the cathode fluid dispensing nozzle outward comprises: removing the metal layer from a first annular area on the surface of the substrate, wherein the first annular area corresponds to the area covered by the cathode fluid dispensing nozzle during a rotation of the substrate; and adjusting the radial position of the nozzle outward to a second annular area on the surface of the substrate, wherein the second annular area immediately circumscribes the first annular area and has the metal layer remaining thereon.
 42. The method of claim 34, further comprising depositing a backside conductive layer on a bevel portion of the substrate extending onto a portion of a backside of the substrate
 43. The method of claim 34, further comprising vacuum chucking the substrate to the rotatable substrate support member and electrically contacting the substrate.
 44. The method of claim 34, wherein electrically contacting the substrate comprises electrically engaging the substrate with a contact ring.
 45. The method of claim 44, wherein the contact ring electrically engages a production surface of the substrate proximate a perimeter thereof.
 46. A method for controlling an electrochemical deplating process, comprising: monitoring at least one of a plating circuit voltage and a plating circuit resistance; adjusting a radial position of a nozzle dispensing an electrolytic solution onto a substrate in order to deplate a metal layer therefrom when at least one of the plating circuit voltage and the plating circuit resistance exceeds a predetermined threshold.
 47. The method of claim 46, wherein monitoring at least one of a plating circuit voltage and a plating circuit resistance comprises utilizing a microprocessor-based controller in electrical communication with at least one electrical sensor.
 48. The method of claim 46, wherein adjusting the radial position of a nozzle dispensing an electrolytic solution comprises selectively pivoting an arm member supporting the nozzle in order to position the nozzle over a circumferential band of the substrate where the metal layer is to be removed.
 49. The method of claim 48, further comprising incrementing through increasing size and abutting circumferential bands across a surface of the substrate.
 50. The method of claim 46, comprising: securing a substrate having the metal layer thereon to a substrate support member in a face up position; rotating the substrate support member; applying an electrical bias to a plating circuit; and dispensing and electrolytic solution calculated to remove the metal onto a surface of the substrate.
 51. The method of claim 50, wherein securing the substrate further comprises electrically contacting the substrate with a plurality of radially positioned electrical contacts.
 52. The method of claim 50, wherein securing the substrate further comprises vacuum chucking the substrate against an anode contact ring having a plurality of radially positioned electrical contacts formed therein.
 53. The method of claim 52, wherein the plurality of radially positioned electrical contacts are in electrical communication with a positive output of a power supply.
 54. The method of claim 51, wherein electrically contacting the substrate further comprises electrically engaging a backside conductive layer deposited on a bevel portion of the substrate and extending onto a portion of a backside of the substrate. 